Surgical Practice Parameters for the Definitive Management of Sacrococcygeal Pilonidal Sinus Disease: Surgeons’ Perspective

Background Sacrococcygeal pilonidal sinus disease (SPD) is a common general surgical condition encountered in practice and predominantly affects young males. Surgical practice parameters for the management of SPD are variable. This study aimed to review current surgical practice parameters for SPD management in Western Australia. Methodology This study conducted a de-identified 30-item multiple-response ranking, dichotomous, quantitative, and qualitative survey of self-reported surgeon practice preferences and outcomes. The survey was sent to 115 Royal Australian College of Surgeons - Western Australia general/colorectal surgical fellows. Data were analyzed using SPSS version 27 (IBM Corp., Armonk, NY, USA). Results The survey response rate was 66% (N = 77). The cohort comprised mostly senior collegiate (n = 50, 74.6%), and most were low-volume practitioners (n = 49, 73.1%). For local disease control, most surgeons perform a complete wide local excision (n = 63, 94%). The preferred wound closure method was an off-midline primary closure (n = 47, 70.1%). Self-reported SPD recurrence, wound infection, and wound dehiscence rates were 10%, 10%, and 15%, respectively. The three high-ranked closure techniques were the Karydakis flap, Limberg’s flap (LF), and Z-Plasty flap. Each surgeon’s median annual SPD procedures were 10 (interquartile range = 15). The surgeons could utilize their preferred SPD closure technique (mean = 83.5%, standard deviation = ±15.6). Univariate analysis showed significant associations between years of experience and SPD flap techniques utilized, with senior surgeons significantly less likely to use either the LF (p = 0.009) or the Bascom procedure (BP) (p = 0.034). Instead, there was a preference for using healing by secondary-intention technique (SIT) compared to younger fellows (p = 0.017). A significant negative correlation existed between practice volume and SPD flap technique utilization, with low-volume surgeons less likely to prefer the gluteal fascia-cutaneous rotational flap (p = 0.049) or the BP (p = 0.010). However, low-volume practice surgeons were significantly more likely to use SITs (p = 0.023). The three most important patient factors in choosing SPD techniques were comorbidities, likely patient compliance, and attitude toward the disease. Meanwhile, factors influencing local conditions included the proximity of the disease to the anus, the number and location of pits and sinuses, and previous definitive SPD surgery. Key informants for technique preference were perceived low recurrence rate, familiarity, and overall good patient outcomes. Conclusions Surgical practice parameters for managing SPD remain highly variable. Most surgeons perform midline excision with off-midline primary closure as the gold standard. There is a clear and present need for clear, concise, and yet comprehensive guidelines on managing this chronic and often disabling condition to ensure the delivery of consistent, evidence-based care.


Introduction Epidemiology and etiology
The term pilonidal is derived from pilus, meaning hair, and nidus, meaning nest. Sacrococcygeal pilonidal disease (SPD) is a common condition with an estimated incidence of 26 per 100,000 and was first described by Herbert Mayo in 1833 [1][2][3][4][5]. SPD is a disease that arises in the hair follicles of the natal cleft of the sacrococcygeal area. Its etiology involves hair (either from the head or growing in the natal cleft itself) causing a local foreign body reaction and the subsequent infection resulting in the formation of pseudocysts, abscesses, and chronic sinuses. It is seen predominantly in young adults of working age and appears in males three to four times more often than in females [1][2][3][4][5][6][7]. It is a chronic disabling condition that causes discomfort, which may interfere with education or work due to poor hygiene, malodor, or itching [1][2][3][4][5][6][7][8][9].
As most patients affected by SPD are between 15 and 40 years of age, the savings to the community in terms of working days lost would be considerable if a simple, cost-effective treatment was available [1][2][3][4][5]. Ideally, definitive treatment of SPD should be cost-effective, require little or no hospitalization, be associated with minimal discomfort and wound care, and have a low recurrence rate to decrease time off work or school.

Management
Many surgical techniques have been described for SPD treatment, yet a lack of consensus on the optimal surgical approach remains. Various surgical procedures for SPD have different complications, primarily recurrence and surgical site infection (SSI) to the less common wound dehiscence, maceration, hematoma, seroma, sphincter damage, and flap edema [1][2][3][4][5][6][7][8][9][10][11]. The American College of Colon and Rectal Surgeons' practice guidelines suggest flap reconstruction techniques as good surgical options for chronic SPD (a strong recommendation based on moderate-quality evidence -grade lb). Still, they do not specify which flap procedure should ideally be used [12]. This is also true for the Italian and German Colorectal Surgeon's guidelines [13,14]. Currently, there are no published Australian guidelines on SPD management.

Previous surveys
A single Australian and several contemporary European surveys have been published reflecting individual surgeon practice preferences for SPD management. The surveys show great variability in surgical practice, techniques, priorities, and perceived outcomes [15][16][17][18]. This study reviewed current surgical practice, preferences, and outcomes for elective SPD surgical management in Western Australia (WA) as part of comprehensive multicenter and patient-reported outcomes. The objective was to find the surgical technique most utilized in elective SPD management and evaluate local disease and patient factors influencing the surgeon's practice preferences. The study also measured individual surgeons' perceived complications, recurrence, surgical site infection, and wound breakdown rates.

Surgeon survey
The local branch of the Royal Australian College of Surgeons (RACS) was approached to provide a census of local fellows. A total of 115 general and colorectal surgeon fellows of the RACS WA branch were invited via email to participate in an online, de-identified survey of self-reported practice preferences and outcomes for elective SPD surgery. The 30-item SurveyMonkey™ containing a mix of dichotomous (yes/no), multiple responses, and free text completion items was conducted from September 2018 to March 2019 (Appendices). The survey included questions used in the prior surveys and additional questions about specific local practice preferences [15][16][17]. Five (monthly) reminder emails were sent during the recruitment period to improve the response rate.
As no local or published standard existed at the time of conception, this paper set a standard for SPD practice workload and dichotomized it into two categories of low and high-volume practice, with lowvolume practice defined as less than 20 SPD procedures per year and likewise high-volume practice to be more than 20 per year.

SPD procedures in practice
The survey presented the respondents with a detailed description of each procedure shown, the list being

Statistical analysis
Baseline characteristics and self-reported practice were described using mean (±standard deviation, SD), median (interquartile range, IQR), and frequencies/proportions as appropriate. Outcomes for continuous unpaired variables were analyzed with the nonparametric independent-sample Kruskal-Wallis and Mann-Whitney U tests. Univariate dichotomous results were compared between groups using the chi-square or Fisher's exact tests with no adjustment for multiple comparisons. Influencing factors and critical informants for practice preferences were captured with the Likert scale and expressed as proportions and a 95% confidence interval (CI). Spearman's rank correlation test assessed the correlation between two quantitative variables. Thematic analysis was done for qualitative data and expressed as logarithmic clouds. All analyses were performed using SPSS Statistics for Mac, version 27 (IBM Corp., Armonk, NY, USA), and a two-tailed pvalue of <0.05 was considered statistically significant.

Permissions
Ethics approval was granted by the lead Human Research Ethics Committee (HREC) -South Metropolitan Health Service Ethics (SMHS) -RGS511 and The University of Western Australia HREC -RA/4/20/4547.

Demographics
The response rate was 66% (n = 77), of which 10 respondents indicated that they do not perform SPD surgery and were removed from further analysis. Overall, 98.5% of the respondents were General Surgeons, of whom 26.9% indicated a Colorectal sub-specialization or interest. The cohort comprised mostly senior collegiate 74.6% but had a trend toward low-volume practice at 73.1% (n = 49). There was an equal distribution of key demographics (  Values are median (interquartile range) and the number of participants (%) unless otherwise indicated. †: SPD = sacrococcygeal pilonidal sinus disease; ‡ Elective = definitive non-acutely infected surgery

Self-reported practice parameters
Most surgeons (94%) perform a complete wide local excision for local disease control, with the preferred wound closure method being an off-midline primary closure at 70.1%.
The reported practice for healing by SIT demonstrated a preference for simple wound packing over vacuum device application at 73.3% and 43.3%, respectively. More than half of the surgeons used a drain routinely, while only about a quarter used methylene blue to define diseased tissues. Most surgeons reported employing supportive measures to facilitate recovery and mitigate the risk of SPD recurrence. Shaving was the most widely adopted standard to keep the natal cleft hair free, while laser treatments were the least ( Table 2). Each surgeon performed a median of 10 elective SPD procedures per year. Most could use their preferred SPD technique with a median of 90% (range = 20-100). Self-reported median SPD recurrence was 10%; other complication rates are reported in Table 3.    Most surgeons reported some familiarity with common SPD procedures presented in the survey, listed in the methods, and provided in the Appendices. The surgeons were most familiar with the KF at 79.1%, while the V-Y was the least familiar at 9%. On preference ranking of SPD procedures, the surgeons chose the KF as their preferred SPD technique, followed by LF, and ZP was their third-ranked go-to technique (  Values are the number of respondents (%) unless otherwise indicated. † 95% CI = confidence interval (Wilson score interval)

Influencing factors
Most surgeon's decision-making in selecting SPD procedures for patients was highly individualized and influenced by patient factors, ranked in order of importance: (i) present comorbidities (e.g., obesity, diabetes), (ii) likely patient compliance with the treatment plan, and (iii) patient attitude toward their disease. This process was also influenced by local disease factors, ranked in descending order of importance: (a) proximity of disease to the anus, (b) number and location of primary pits and secondary sinuses, (c) and previous SPD surgery (  When asked to elaborate on their practice flexibility, 67.2% of the surgeons strongly agreed to use the same SPD technique for all their patients independent of the affected area. Respondents were asked to rank motivators and values in selecting particular SPD procedures, with personal preference as the main guide (82.1%). Almost half of the participating surgeons (49.3%) took into consideration patient preference in the selection process. About 79.1% of respondents cited patient factors (compliance, obesity, attitude toward the disease, diabetes) as enormously influential to their decision-making. The surgeons rated the severity or stage of local disease as the most influencing factor in selecting an SPD procedure, with 89.6% of the surgeons agreeing.

Years of experience and associations
The surgeons in the mid-tier group (5-10 years) performed significantly more SPD procedures per year, with a median of 15 (IQR = 10) procedures (p = 0.016). There were no statistical differences in the estimation rates of complications (recurrence, infection, and dehiscence) between the years of practice tiers. There were, however, significant statistical differences in the SPD technique choices being influenced by either patient preferences (p = 0.028) or by patient factors such as comorbidities (p = 0.004) between tiers of surgical experience, with more experienced surgeons (>10 years of experience) less likely to put more emphasis on these parameters ( Table 6).

N = 67 <5 years Mdn (IQR) † 5-10 years Mdn (IQR) >10 years Mdn (IQR) P-value ‡
Procedures per year (n) 10 (13) 15 (10) Technique is influenced by patient factors (n) Univariate analysis showed significant associations between years of experience and SPD flap techniques utilized. More senior surgeons were significantly less likely to prefer the Limberg's flaps (p = 0.009) or the Bascom procedure (p = 0.034). Senior surgeons were more significantly associated with favoring the healing by secondary intention pathway than younger fellows (p = 0.017). Regarding supportive measures, the senior collegiate group was less inclined to set up dedicated follow-up clinics (p = 0.050) nor recommend waxing as a routine (p = 0.048).
Further analysis showed significant associations between years of experience and the factors that influenced the selection of SPD techniques. The choice of SPD procedure among the more senior surgeons was reported as less likely to be influenced by either patient preferences (p = 0.008) or patient factors (p = 0.006). Interestingly, no statistical differences existed in which group dealt with the complex cases more often. Still, there was a trend toward the more senior cohort managing such cases at 50% compared to 20% and 30% for the lower-tier groups, respectively (p = 0.888).

Practice volume
On a sub-analysis of SPD practice workload, dichotomized into low and high-volume practice as defined in methods, the high-volume group mean (procedures per year) was 25.6 (SD = ±9.7) (p < 0.001). There were no statistical differences between the two volume groups for estimated complication rates (recurrence, infection, and dehiscence). However, there were significant statistical differences in the SPD technique choices being influenced by either surgeon's personal preferences (p = 0.029) or other specified external factors (p = 0.047) between the groups. High-volume surgeons were more likely to choose a technique based on personal preference (94.4% vs. 77.6%). Meanwhile, low-volume surgeons cited other specified factors higher in the decision-making process ( Table 7).

Associations for practice volume
Univariate analysis showed significant negative associations between practice volume and SPD flap technique utilization, with low-volume surgeons less likely to prefer the gluteal fascio-cutaneous rotational flap (p = 0.049) nor the Bascom procedure (p = 0.010). However, a significant positive association existed between low-volume practice surgeons choosing to use the healing by secondary intention pathway (p = 0.028). No statistically significant differences existed between the two volume groups for supportive measure recommendations. Still, there was a clinically significant trend for the low-volume group's broad adoption of supportive measures ( Table 8).

N = 67
Total cohort Low volume (<20 procedures) High volume (>20 procedures)  Univariate analysis showed significant associations between the volume of practice and factors that influenced SPD techniques, with the low-volume group significantly associated with having a less flexible approach; two-thirds (64.4%) reported using the same SPD techniques all the time regardless of confounding patient or local disease factors compared to only one-third (35.6%) in the high-volume group (p = 0.038).
Interestingly, there were no statistical differences between the two groups for complex cases, but there was a preponderance of low-volume surgeons managing such cases (p = 0.097) ( Table 9).

N = 67
Total cohort Low volume (<20 procedures) High volume (>20 procedures)  Values are the number of respondents (%) unless otherwise indicated.

Thematic analysis
For the healing by secondary intention pathway, when opting to pack the wound, the most cited preferential packing material was Kaltostat (62.2%), ribbon gauze (15.6%), and Aquacel (13.3%). The logarithmic thematic pictorial representation is demonstrated in Figure 1a. The key informants for SPD technique preference were low recurrence rates, familiarity, and overall good outcomes (Figure 1b).

Practice parameters
SPD is a common general surgical condition encountered in practice, predominantly in the young adult male working population [1][2][3][4][5][6][7]. The ideal definitive treatment for SPD should be one that requires little to no hospitalization, is associated with minor discomfort, has low recurrence rates to minimize time off from work or school, and has a low burden on the healthcare system [1][2][3][4][5]. Multiple surgical techniques have been developed, adapted, and modified to address this vexatious disease. Nevertheless, a lack of consensus on the optimal SPD technique persists due to the challenging nature of its management, with no one approach better than another [1][2][3][4][5][6][7]. This study's results confirm that SPD surgical practice parameters remain variable in utilization and application. Many participants reported using more than one flap technique, with 18% also reporting using a combination of primary flap closure and SIT techniques.

Practice preferences
Consistent with the published literature, in this study, most surgeons still prefer to perform a complete wide local excision (94%) for local disease control, with a preference for an off-midline primary closure (70%), deemed best practice, as recommended by the current American [12] and European Guidelines [13,14]. More than half of the surgeons used a drain as a routine. The routine use of surgical drains in conjunction with flap techniques has demonstrated a decrease in recurrence rates or surgical site infections; however, it is associated with decreased incidence of flap edema. Therefore, the American practice guidelines [12] advocate for the individualized use of surgical suction drains, a strong recommendation based on moderatequality evidence (grade lB).

Methylene blue
About a quarter of the respondents in this study reported using methylene blue for tissue definition. However, its use remains controversial because it can be associated with significant staining of normal tissue resulting in unnecessarily extensive excisions. Additionally, various studies have not demonstrated a substantial reduction in recurrence rates with the additional staining step. Moreover, the second part of this study (retrospective decade review of all local elective SPD outcomes) interestingly showed that methylene blue use was significantly and independently associated with achieving clear surgical margins on histopathology, which were then subsequently associated with low rates of recurrence (p < 0.001) [19].

Breadth of practice
This study captured current practice parameters from a diverse pool of experienced surgeons and showed that most responding participants were senior collegiate (74.6%). Consistent with published practice volume literature [15][16][17][18], this study showed a predominantly low volume of local SPD practice (73.1%). No statistical differences were reported between the low-volume and high-volume groups' self-reported recurrence rates or other key complication rates. Additionally, low-volume surgeons were reported to perform a more significant proportion of complex cases. It is possible that the low-volume practice was established to serve uncomplicated cases, thus freeing up more time and operative space for more complex and time-consuming cases to be done selectively to reduce the risk of surgeon fatigue and poor patient outcomes; however, this does not appear to be the case. Previous studies have argued that SPD practice should be concentrated in high-volume centers [15][16][17]. However, this survey highlights that many complex cases were performed at the low-volume center, with no significant differences in reported outcomes. Therefore, it may seem counterintuitive for SPD procedures to reallocate cases based on the argument of low-volume practitioners. This may be an area of further investigation as this study was not designed to explore this subject matter but provides insight into potential future studies.

Practice flexibility
It is well-known that there is no one-size-fits-all approach in SPD management. This study identified that more than two-thirds of the surveyed surgeons reported using the same SPD technique for all their patients regardless of the circumstances; this is not ideal as it fails to consider each patient's conditions, such as the severity of disease and natal anatomy, which are factors known to influence outcomes. The low-volume group was significantly more flexible in the SPD approach and application. The modest adoption of SIT reported in this study is a concern because SIT is well documented in the literature to be associated with significant human factor costs (prolonged time to heal and pain) and is resource-intensive to the healthcare system. Moreover, SPD mainly affects young patients, who make up the bulk of the workforce; thus, performing SIT procedures on them, which are known to have prolonged healing and translate into lost productive economic time, should be avoided. Therefore, it can be argued that emphasis should be given to technique selection and consideration of patient factors to ensure minimal disruption to the patient's daily life and productive economic participation while attaining a low recurrence rate.

Supportive measures
Supportive measures such as dedicated follow-up clinics or hair removal recommendations after definitive SPD procedures remain inconsistent. In this study, the surgeons' self-reported practice of implementing supportive measures received a mixed response inversely associated with surgical experience. The senior collegiate group was less inclined to set up follow-up clinics or recommend routine waxing. The analysis of utilizing these measures based on volume practice showed no statistical significance. However, there was a noticeable trend for the low-volume group's broader implementation of these measures. A recent systematic review by Pronk [20] showed the benefit of implementing supportive measures for risk reduction; however, due to the limitations of the review, a recommendation was made for further high-quality RCT studies. It is reasonable to adopt these secondary preventative measures post-definitive surgery as these simple measures are not inferior to the option of doing nothing [21].

Practice guidelines
The three parts of this study reflect the vast variability in SPD treatment and management in the Australian cohort [19,21]. The mixed responses from the surgeons' self-reported practice showed different levels of familiarity with SPD techniques, differing routines regarding flexibility in technique selection based on key informants, and supportive measurements. The American [12], Italian [13], and German [14] surgical societies have published guidelines to standardize the management of a seemingly simple disease that can unfortunately quickly become a persistent burden. It is perhaps time for Australians to develop and establish a national guideline built on the foundation of international data and further adapted with local data to reflect and better serve the Australian patient population.

Study limitations
There are certain limitations and strengths of this study. This study's comprehensive and circular/resampling nature is a strength that gives it internal validity by capturing similar responses at different stages of the survey. This is further augmented by the high response rate from an anonymous random sample of surgeons. There remains a small risk of non-response bias, but the high response rate should mitigate significant influence on results. One of the limitations of this study is the inclusion of selfreported clinical practice, as it would be impractical to verify and assess each respondent's current practice. However, numerous studies have defended its continued use because of its high sensitivity and moderate specificity, especially in health professionals' studies [22]. While this study acknowledges that limited value is placed on survey questionnaires in terms of drawing definitive conclusions, there is an undisputed value that this survey adds to the growing body of evidence in highlighting informative key and essential variations in current SPD practice. An outcome congruent with findings in other reported studies, this, in turn, gives this study external validity.

Future direction
A comprehensive guideline by the Colorectal Surgical Society of Australia and New Zealand would help bridge the knowledge gap in managing this debilitating disease, which primarily afflicts a young population and active economic participation.

Conclusions
Surgical practice parameters for managing SPD remain highly variable. Most surgeons perform midline excision with off-midline primary closure as the gold standard. There is a clear and present need for clear, concise, and yet comprehensive guidelines on managing this chronic and often disabling condition to ensure the delivery of consistent, evidence-based care.
This paper is the opening salvo and is followed by a compressive medical records review (inpatient and outpatient) to capture the patient journey before closing the loop with a novel and unprecedented prospective follow-up of SPD patient-reported outcomes to truly capture the entire patient journey that can inform further practice.

Additional Information
Disclosures